[Etiology and physiopathology of Basedow's disease].
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Animals↗
Biomedical subjects
T Akamizu
Publications and source records attributed to T Akamizu.
Familial clustering of thyroid stimulation-blocking antibody.
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Female↗
Preferential localization of human CD5+ B cells in the peritoneal cavity.
In a transgenic mouse model of autoimmune haemolytic anaemia, CD5+ B lymphocytes localized in the peritoneal cavity are shown to play an important role in the onset of autoimmune disease. The authors have examined whether CD5+ B cells are present in the peritoneal cavity of 12 human individuals with non-invasive gastrointestinal tumours and found that in humans CD5+ B cells preferentially lodge in the peritoneal cavity as compared to the peripheral blood and spleen while the numbers of the peritoneal B lymphocytes in humans are much lower than in mice and vary widely between individuals.
Animals↗
Differential expression of thyrotropin receptor mRNA in the porcine heart.
Thyrotropin receptor (TSHR) mRNA expression has previously been detected in human heart, suggesting a possible role for the receptor in cardiac function and pathophysiology. In the present study we examined the regional distribution of TSHR mRNA in pig heart to map potential cardiac sites of TSH action. Polyadenylated mRNA extracted from thyroid, atria, ventricles, aorta, coronary arteries, epicardial fat, and purified preparations of atrial and ventricular cardiomyocytes was subjected to reverse-transcriptase polymerase chain reaction (RT-PCR) using primers designed to amplify a 311 base pair (bp) DNA segment of the human TSHR. After reverse transcription of 100 ng mRNA, cDNA was amplified by PCR using TSHR primers and compared by electrophoresis on 2% agarose gels. Relative levels of TSHR cDNA (normalized to glyceraldehyde 3-phosphate dehydrogenase [GAPDH]) were as follows: Coronary arteries, epicardial fat > right atrium > left atrium > right ventricle, aorta > left ventricle, ventricular cardiocytes. In contrast to ventricular cardiocytes, purified atrial cardiocytes expressed levels of TSHR mRNA readily detectable with RT-PCR. These findings demonstrate that TSHR mRNA expression in porcine heart varies regionally, and furthermore suggest that areas of highest expression (coronary arteries, adipose tissue, right atrium) are potential sites for a functional or pathologic role of the TSHR.
Adipose Tissue↗
Effectiveness of a short-term steroid treatment on the reduction in goiter size in antithyroid drug-treated patients with Graves' disease.
Reduction of goiter size is one of the criteria necessary to determine clinical remission in antithyroid drug (ATD)-treated Graves' patients. To facilitate goiter reduction or to achieve quick remission, a short-term steroid treatment was administered to 5 Graves' patients. These patients had been treated with ATD for a considerable period of time, had maintained euthyroidism with negative or weak thyrotropin-binding inhibitor immunoglobulin (TBII), but still had an enlarged goiter and remained T3 unsuppressive. Betamethazone was initially given 1.5 mg daily and then gradually tapered to 0 mg for 3 months. Compared to the 6-month observation period or the pre-medication period, goiter reduction exceeding 0.7 cm was achieved in all 5 patients during the steroid treatment. These reductions partly reversed to an extent smaller than pre-treatment levels in 2 patients, but continuous goiter reductions were observed for at least 3 months after steroid cessation in 3 patients. In 2 of these reduced goiter patients, T3 suppressibility was confirmed, and they were diagnosed in remission. During steroid administration, serum T3 and TSH concentrations were lowered but reversed shortly, serum fT4 concentrations did not change, and TBII levels became negative in all patients including the 2 with weak positive values before the treatment. In conclusion, a short-term steroid treatment for goitrous ATD-treated Graves' patients appears promising in achieving goiter reduction or remission.
Adult↗
Pathogenesis of Graves' disease: molecular analysis of anti-thyrotropin receptor antibodies.
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Antibodies, Monoclonal↗
Association of autoimmune thyroid disease with a microsatellite marker for the thyrotropin receptor gene and CTLA-4 in a Japanese population.
To examine the genetic contribution of the thyroid-stimulating hormone receptor (TSHR, or thyrotropin receptor) gene to autoimmune thyroid disease (AITD), we identified a dinucleotide repeat polymorphism near the TSHR gene that mapped to an 8.6 cM interval between D14S74 and D14S55 on the long arm of human chromosome 14. Association studies revealed a significant difference (p = 3.8 x 10(-5) between the TSHR microsatellite allele frequency distribution in 81 unrelated Japanese AITD patients and 113 Japanese controls, with a significant increase in the 180 pb allele (allele 1) of the microsatellite sequence (p = 5.8 x 10(-7). The risk for AITD with the 180 bp allele was 3.5, with association highly significant in female patients (p = 1.1 x 10(-5) and less dramatic, but still significant, in male patients (p = .02). These results suggest that the 180 bp allele of the TSHR microsatellite is associated with a susceptibility locus for AITD in Japanese patients. Two additional genetic markers have been evaluated for association in the Japanese AITD patients. The TSHR codon 52 (C52-->A52) transition mutation was not observed in the Japanese. A polymorphism for the CTLA-4 gene was genotyped and, while association with AITD was not observed (p = .15), a significant association was observed between CTLA-4 alleles of 110 bp (p = .01) and 106 bp (p = .004) and susceptibility to primary hypothyroidism or idiopathic myxedema, respectively.
Abatacept↗
Molecular analysis of stimulatory anti-thyrotropin receptor antibodies (TSAbs) involved in Graves' disease. Isolation and reconstruction of antibody genes, and production of monoclonal TSAbs.
Anti-thyrotropin (TSH) receptor autoantibodies (TRAbs) have been known to be involved in Graves' disease. To understand the molecular mechanism for pathogenesis of TSAbs in Graves' disease, we isolated and reconstituted the Ig genes of EBV-transformed B cell clones producing monoclonal thyroid stimulating Ab (TSAb) obtained from patients with Graves' disease. The V region genes of Ig heavy (H) and light (L) chains of two TSAb clones, IgG clone B6B7 and IgM clone 101-2, were isolated by the PCR. Nucleotide sequencing analysis revealed that germ-line VH and VK segments widely used for autoantibodies including the previously isolated TRAbs were utilized in the two clones. A significant number of somatic mutations were found in V regions of both clones, indicating the involvement of somatic mutations for the TSAb specificity. Reconstituted Ig H and L chain genes of the two clones were stably introduced into myeloma cells for IgG1 production. IgGs purified from cultured supernatants of both transfectants exhibited significant TSAb activities, while they did not inhibit TSH binding to the receptor. The successful expression of recombinant TSAbs in eukaryotic cells will provide opportunities to apply them to various pathophysiologic, diagnostic and therapeutic investigations in autoimmune thyroid diseases.
Antibodies, Monoclonal↗
Laboratory tests necessary at the first examination of patients with suspected thyroid disorders.
In order to determine what and how many test items are necessary for the initial tests when examining patients with thyroid disorders, a questionnaire was sent to the council members of the Japan Thyroid Association. Thyroid disorders were divided into 4 categories; hyperthyroidism, hypothyroidism, diffuse goiter, and nodular goiter. The questionnaire was designed to assess: 1) tests routinely ordered at the initial examination; 2) minimum test battery necessary; 3) the 5 most important tests in order; and 4) selection of only 2 tests at most. The data on 112 completed questionnaires were collected and analyzed. When the choice was limited to only 2 tests, TSH and fT4 were commonly selected for hyperthyroidism hypothyroidism and diffuse goiter, but these 2 tests would be insufficient for the differentiation of disorders. In the case of nodular goiter, ultrasonogram and fine needle aspiration biopsy (FNA) were selected. The mean number of routinely ordered tests was 6.62 +/- 2.00 (S.D.) for hypothyroidism and 8.06 +/- 2.48 for nodular goiter, but many fewer tests were cited as absolutely necessary. In hyperthyroidism, 4.56 +/- 1.92 tests were required, in hypothyroidism 4.39 +/- 1.92, in diffuse goiter 4.93 +/- 1.75, and in nodular goiter 5.15 +/- 2.13. Most of the function-related tests, ultrasonogram and autoantibodies were commonly selected, while TBII and thyroid 123I or 99mTcO4 uptake in hyperthyroidism, and FNA, Tg and scintigram in nodular goiter were considered to be for specific purposes. Summarizing all these, the authors propose 5 or 6 tests to be necessary as the initial tests when examining patients with 4 individual thyroid disorders.
Autoantibodies↗
Cardiomyopathy associated with Graves' disease.
Cardiovascular changes associated with Graves' disease are generally considered to be secondary to the increased levels of thyroid hormone. We describe a case of Graves' disease in a 25-year-old man, who developed cardiomyopathy with severe heart failure. Pathological examination of the myocardial biopsies showed fibroblast infiltration and degenerative changes. After the cardiomyopathy subsided the patient developed a goitre and signs of hyperthyroidism, followed by Graves' ophthalmopathy, which was treated successfully with a combination of high-dose corticosteroids and orbital radiotherapy. These findings suggested a common pathogenesis for the cardiomyopathy and ophthalmopathy, and prompted us to investigate the expression of TSH receptor (TSH-R) in human heart. TSH-R mRNA was identified in human heart using the reverse transcriptasepolymerase chain reaction (RT-PCR) and DNA sequencing. Taken together, these data suggest that autoimmunity against the TSH-R might contribute to both the cardiomyopathy and ophthalmopathy in similar cases of Graves' disease.
Adult↗
Isolation of Epstein-Barr-virus-transformed lymphocytes producing IgG class monoclonal antibodies using a magnetic cell separator (MACS): preparation of thyroid-stimulating IgG antibodies from patients with Graves' disease.
In autoimmune diseases, IgG class autoantibodies are generally considered to be more pathognomonic than IgM class ones. Although Epstein-Barr virus (EBV)-transformation of lymphocytes is a useful method to obtain human monoclonal autoantibodies, it tends to result predominantly in IgM-producing cells. We depleted IgM+ cells before EBV-transformation with a Magnetic Cell Separator (MACS) in order to increase the chance of acquisition of cells producing IgG class anti-thyrotropin (TSH) receptor antibodies (TRAb). As a result, we obtained four independent B cell clones producing IgG class monoclonal thyroid-stimulating antibodies (TSAb) from three patients with Graves' disease. None of these clones showed any TSH binding inhibitor immunoglobulin (TBII) activity, suggesting independence of TSAb-producing lymphocytes from those producing TBII.
Antibodies, Monoclonal↗
Statistical analysis of functional region(s) of the TSH receptor.
In this study, we apply recently developed methods to evaluate the thyrotropin receptor (TSH-R). These methods are called deviation (DEV) model, deviation decrease (DD) and DEV/DD analyses, and are based on deviation of amino acid sequences. A 3-dimensional structure model of TSH-R was graphically constructed, and found to possess a large central cavity (donut-like structure). The N-terminus was found to be in the center of the whole extracellular structure and to form a part of the bottom of the cavity. High DEV values indicate deviated amino acid compositions in the protein and were seen in 7 regions, 6 of which were found to be in regions with hydrophilic and acrophilic character. On the basis of the analysis of intra-molecular cis-acting relationships, 7 pairs of regions were presumed to be closely related. Further, when 3 exoplasmic loop lesions were analyzed similarly, 3 other regions were shown to have a close relationship with the cell surface. DEV/DD values were applied to predict the interface of TSH-R with trans-acting molecules such as TSH-R antibody or TSH. The regions in association with trans-acting molecules were seen in 14 regions, 11 of which included the high DEV regions. Both of the TSH-R specific regions in the N- and C-terminal side, especially the latter, were found to be the major components.
Amino Acid Sequence↗
Establishment and characterization of an antihuman thyrotropin (TSH) receptor-specific CD4+ T cell line from a patient with Graves' disease: evidence for multiple T cell epitopes on the TSH receptor including the transmembrane domain.
From the peripheral lymphocytes of a patient with Graves' disease, we established a T cell line using its reaction to a pool of 49 synthetic peptides corresponding to the entire human thyrotropin receptor (TSHR) sequence. This T cell line showed a specific response to the pool of peptides in a microproliferation assay (stimulation index: 4.8). Flow cytometry analysis revealed that the cell surface markers were CD4+ CD8-, T cell receptor (TcR) alpha beta+, and Tcr gamma delta-. To investigate T cell epitopes on TSHR, the T cell line reacted well against three groups: the N-terminal (amino acids 31-169) and C-terminal (338-420) regions of the extracellular domain and the N-terminal half (441-661) of the transmembrane domain of the receptor. This suggests a multiplicity of T cell epitopes on the TSHR, and was further supported by analysis of TcR gene expression in the cell line that showed the expression of 5 V alpha genes; V alpha-1, 2, 10, 20, and w25. In conclusion, the results of the present study indicated multiple T cell epitopes on the TSHR molecule including the transmembrane domain.
Adult↗
Molecular studies on thyrotropin (TSH) receptor and anti-TSH receptor antibodies.
Cloning of TSHR gene and some subsequent studies using the gene were described. Enormous numbers of studies have been performed since the cloning of TSHR gene. Recent molecular studies on TSH receptor and TSHRAb gave various impacts on thyroidology and are resolving past problems. We mainly focused on regulation, processing and glycosylation, TSH- and TSHRAb binding sites, T cell epitopes, and signal transduction of TSHR. Furthermore, we isolated and characterized TSHRAb genes using lymphocytes producing monoclonal TSHRAb obtained from patients with Graves' disease and primary hypothyroidism. Thus, both antigen and antibody genes are cloned. Combined use of these genes will help to investigate the interactions between TSHR and TSHRAb, and may be expected to contribute to the understanding of molecular mechanisms underlying the pathogenesis of autoimmune thyroid disease as well as the physiology of the thyroid gland.
Amino Acid Sequence↗
A hyperthyroid patient with Graves' disease who was strongly resistant to methimazole: investigation on possible mechanisms of the resistance.
We treated a patient who was hyperthyroid due to Graves' disease and strongly resistant to methimazole (MMI): in spite of good compliance, she needed 150 mg of MMI daily to control her hyperthyroidism. To elucidate the reasons of resistance to MMI, her serum and intrathyroidal MMI concentrations were determined by high pressure liquid chromatography (HPLC). After taking a 30 mg dose of MMI, she had a similar serum MMI concentration-time curve to that of a normal subject: drug malabsorption and rapid drug metabolism were not evident when studied after surgical treatment. After her serum containing MMI was incubated with Protein G, the MMI concentration of the fraction not bound to Protein G did not change significantly from that of untreated serum: the possibility of anti-MMI IgG antibody production was considered unlikely. Furthermore, the intrathyroidal concentration of MMI in a surgically obtained tissue specimen was 3 micrograms/g wet tissue and appeared to be comparable with those of other Graves' tissues reported. Considering that the patient had been taking 150 mg per day of MMI by the time of thyroidectomy, her intrathyroidal MMI concentration was relatively low, suggesting possible impairment of intrathyroidal MMI accumulation. The possibilities of impaired intrathyroidal actions and the severity of hyperthyroidism, especially high T3 levels, also remained as possible causes. In conclusion, here was a severely hyperthyroid patient who was poorly responsive to conventional doses of MMI, and impairment of thyroid uptake of MMI or of pathways after uptake were considered as possible mechanisms.
Adult↗
Thyroid-stimulating antibodies in sera from patients with Graves' disease are heterogeneous in epitope recognition.
Two synthetic peptides, P354-14 (amino acid nos. 354 to 367) and P338-16 (nos. 338 to 353), corresponding to the partial amino acid sequences of the hTSH receptor structure were studied for their ability to bind specifically serum IgGs from patients with Graves' disease and to inhibit thyroid stimulating TSH receptor antibody (TSH-R SAb) activity. IgG binding was measured by an ELISA using sera from 102 Graves', 20 Hashimoto patients, and 9 normal subjects. Both peptides showed significantly increased IgG binding of Graves' sera compared with those of Hashimoto and normal sera. There was a significant correlation (r = 0.529) between the amount of IgG bound by the two peptides, but neither of these values correlated well with their TSH-R SAb activity nor thyrotropin-binding inhibitor TSH receptor antibody (TSH-R IAb) activity. TSH-R SAb inhibiting effects of these peptides were then analysed by measuring TSH-R SAb activity after incubation with the peptides. Among eight Graves' IgGs tested the TSH-R SAb activity of three was inhibited by both peptides, two were inhibited only by P354-14 and three were not affected by either. These TSH-R SAb inhibiting effects were dose-dependent and reproducible. To confirm these findings, a peptide-sepharose gel affinity absorption study was performed. Eleven Graves' IgGs were applied to both peptide gels and the TSH-R SAb activity of the unabsorbed fraction was measured. The TSH-R SAb activity of five IgGs was strongly absorbed only by P354-14 and five others were absorbed by both peptides to an almost similar extent.(ABSTRACT TRUNCATED AT 250 WORDS)
Absorption↗
Presence of heterogeneous thyroid-stimulating antibodies in sera from individual Graves' patients as shown by synthesized thyrotropin receptor peptide application: evidence showing two independent epitopes and a possible recognition of two epitopic regions by one antibody molecule.
To define the epitope(s) of stimulating thyrotropin receptor antibody (TSH-R-Sab), we synthesized 19 oligopeptides covering almost all amino acids of the extracellular domain of the human TSH-R and studied these effects on the inhibition of one TSH-R-Sab activity. Four of the 19 peptides encompassing residues 31-50 (P31-20), 91-119 (P91-29), 287-304 (P287-18) and 354-367 (P354-14) were found to show significant TSH-R-Sab inhibition and to have similar effects on the other three Graves' immunoglobulins. When these peptides were applied in combination with P354-14 only P287-18 revealed additional effects but the other two combinations did not. Furthermore, sequential addition of these peptide pairs confirmed the additional effects of P287-18 and P354-14. Sequential peptide-affinity gel studies were then performed. Most of the TSH-R-Sab activity in the unabsorbed fraction from P287-18 gel was absorbed to a subsequent P354-14 gel and the eluted fraction from P287-18 mostly remained unabsorbed by the P354-14 gel. On the other hand, most of the unabsorbed fraction from P91-29 gel remained unabsorbed even by the subsequent P354-14 gel. When a P354-14 affinity gel-purified TSH-R-Sab immunoglobulin was labeled and evaluated for its binding to FRTL-5 cells, additions of original immunoglobulin, P354-14 and P91-29 resulted in significant inhibition of the binding but P287-18 did not affect either. From these results, it was concluded that most of the individual Graves' immunoglobulins contain at least two heterogeneous moieties with TSH-R-Sab activity, one of which binds P354-14 and the other binds P287-18. Further, P354-14 and P91-29 were indicated to bind the same molecule of TSH-R-Sab immunoglobulin.
Absorption↗
[Recent progress in the diagnosis of thyroid diseases].
The diagnosis of thyroid diseases is mainly divided into three categories: morphological, functional and etiological diagnoses. Great progress has recently been seen in each field. For example, in the functional diagnosis, improvement of sensitivities and development of non-radioimmunoassays have been achieved in the measurement of hormone level. Especially, improvement of thyrotropin (TSH) measurement has greatly contributed to precise evaluation of thyroid function. In the etiological diagnosis, marked improvements have been made by genetic analyses. Mutations of genes of hormones, their receptors and other proteins related to thyroid function have been revealed as causes of various thyroid disorders, such as cretinism, hyperthyroidism and tumors. Immunological analyses also showed significant progress, i.e., improvement of anti-thyroglobulin and anti-thyroid peroxidase antibody measurements. It is also necessary for all three diagnostical approaches to be improved concomitantly in the future.
Humans↗